BAGHDAD (Reuters) -- A suicide bomber detonated a vest packed with explosives at a cafe south of Baquba in Iraq's Diyala province on Tuesday, killing six people and wounding 10, police have said.

The attack took place in the town of Buhriz, killing Leith Mishaan, the local head of a government-allied Sunni Arab militia, who was at the cafe with other members of his group.

The mostly Sunni Muslim militias sprang up in 2006 with backing from the U.S. military and have helped curb Al-Qaeda and other insurgents. They are now paid by the Iraqi government.

Violence has fallen sharply in Iraq since the 2003 U.S.-led invasion, but the insurgency unleashed by the invasion remains entrenched in religiously and ethnically mixed Diyala and other parts of northern Iraq, including the violent city of Mosul.

Insurgents have been able to exploit religious and ethnic divisions in those areas to remain effective after being driven out of former strongholds elsewhere in Iraq.